Russia's President Dmitry Medvedev (r.) listens to his Brazilian counterpart Luiz Inacio Lula da Silva during a joint news conference in Moscow's Kremlin May 14. Russia participated in the deal brokered this week by Turkey and Brazil to exchange low-enriched uranium for fuel rods in Tehran.

Moscow's willingness to back the new sanctions, which include a partial arms embargo and financial strictures, represents a significant evolution of Russian policy from its previous rejection of such strong measures.

But there are limits. President Dmitry Medvedev's wish to move toward a more pro-Western orbit, outlined in a leaked foreign policy review last week has already run up against resistance from vested interests in Russia's military-industrial establishment, experts say.

"Relations with the US have become more important than relations with Iran. Medvedev has changed the priorities, and you do see the results" says Viktor Kremeniuk, deputy director of the official Institute of USA-Canada Studies in Moscow. "But that doesn't mean Russia's preparing to abandon Iran. Medvedev cannot go against important Russian lobbies, who have vested interests that can't be ignored."

Sanctions will not stop anti-aircraft systems from reaching Iran

On Friday Mikhail Margelov, the head of the foreign affairs commission of the Federation Council, Russia's upper house of parliament, insisted that any sanctions resolution will not prevent Russia from honoring an oft-delayed contract to deliver advanced, long-range S-300 anti-aircraft systems to Iran.

"The draft [sanctions resolution] will not hit current contracts between Russia and Iran," the independent Interfax news agency quoted him as saying. "It should be remembered that Russia is a responsible seller of its products on foreign markets and we are not interested in the militarization of the Middle East."

The $1 billion Bushehr plant on the Persian Gulf, which has also been the subject of repeated delays, will be completed and put into operation within three months, the head of the state-run atomic power agency, Sergei Kiriyenko, told journalists on Thursday.

"We expect the nuclear power plant will be launched by August if everything goes according to plan," Mr. Kiriyenko said. "The resolution on Iran being drawn up [in the Security Council] will not affect these plans."

Iran-Russia relations 'growing worse'

But some Russian experts argue that such investments are now largely symbolic, meant to emphasize Moscow's "independent position" rather than reflecting any large, ongoing Russian economic interests in Iran.

"Our relations with Iran have been growing worse since the presidential elections in Iran last year," says Vladimir Yevseyev, an expert with the Center for International Security in Moscow. "Our trade turnover with Iran is low, around $3 billion annually." He adds that Russian energy companies Lukoil and Gazprom have largely departed from Iran, despite big hopes for cooperation in previous years.

The same is true of nuclear cooperation, where former talk of building up to eight Russian nuclear power plants in Iran has been scaled back to just completing Bushehr, says Alexei Malashenko, a Russia expert with the Carnegie Center in Moscow.

"They've announced intentions to finish Bushehr at last, probably because doing so will free Russia's hands [with respect to Iran]," he says. "This has been a problem for us for too long."

Russia puts faith in Obama

Mr. Malashenko says Medvedev's new West-centered foreign policy approach is based on big hopes that President Barack Obama means what he says about his policies of greater engagement with Russia and not launching a military strike against Iran's nuclear program.

"At the moment in Moscow they are shaping policies to fit Obama's line, and everyone is very sure that [tougher sanctions against Iran] are not leading to war," he says. "Russian leaders are absolutely certain that Obama has ruled out military action against Iran."

Experts say that Russia also showed its chops as an international team player by participating in the deal brokered this week by Turkey and Brazil to exchange low-enriched Iranian uranium for fuel rods to be used in a US-built medical reactor in Tehran.

"This issue was probably discussed during Medvedev's visit to Turkey last week, and the Brazilian president's visit to Moscow earlier this week," says Mr. Yevseyev. "It is Russia that will likely carry out the enrichment of uranium to be supplied to Iran under that deal."